Neuer Zeitschriftenbeitrag von Wenzel et al., 2026
Biological methanation of hydrogen (H2) and carbon dioxide (CO2) in trickle bed reactors (TBR) is considered a promising technology for energy conversion, especially in the context of energy storage via Power-to-Gas (PtG). This study investigates the restart of a pilot-scale thermophilic TBR after 1.5years of uncontrolled dormancy under real wastewater treatment plant conditions to upgrade raw biogas from the local digester to synthetic natural gas quality (CH4 > 95%).
Molecular biological investigations have indicated that it might be feasible to recommend the operation of the reactors, even following a highly protracted period of inactivity. The results demonstrate that the reactor can be successfully reactivated without re-inoculation, indicating a high resilience of the biofilm-based microbial community. Following the addition of digester supernatant as a nutrient and buffer source, methane concentrations above 95% were achieved within a few hours. Stable operation was strongly linked to maintaining NH4+ concentrations above 400mg/L and controlled pH conditions, highlighting the importance of process stabilization during restart. Furthermore, the integration of a 5kW AEM electrolyzer enabled on-site hydrogen production, demonstrating the feasibility of coupling biological methanation with renewable energy supply (e.g., through photovoltaic). Overall, the results provide new insights into rapid reactor restart, process resilience, and the practical implementation of PtG systems under real operating conditions.